Because polyphenols contained in plants produce an antioxidation effect, they have been used in a large variety of food products, drugs, and cosmetics. Proanthocyanidins are polyphenols that produce an especially strong antioxidation effect. As described in Patent Reference 1, proanthocyanidins are polyphenols contained in a large amount in plants such as grapes, apples, persimmon, and pine, and because of their especially strong antioxidation effect, they are used for a variety of applications described, for example, in Para. Nos. 0031-0034 of Patent Reference 1.
[Patent Reference 1]
Japanese Patent Application Laid-open No. 2001-158739.